Infertility is a complex problem affecting approximately 15% of married couples in the U.S. who desire a child. The purpose of this study is to evaluate the effect several reproductive, behavioral, medical, and occupational exposures have on the occurrence of involuntary female infertility. To accomplish this, data from a recent population-based case-control study of contraceptive use and the subsequent risk of infertility will be utilized. In this initial study, an attempt was made to identify all women in King County (WA) who sought medical treatment for infertility during 1979-81. Interviews were carried out with approximately 1000 infertile women, and with approximately 1000 control women who were matched to the cases on demographic criteria, and who had successfully achieved conception at the time the corresponding case began her unsuccessful attempts to do so. The data include detailed information on these womens' past reproductive, contraceptive, and sexual practices, occupational exposures, and use of alcohol, tobacco, drugs, and caffeine. Specific exposures to be explored for their association with the occurrence of different types of infertility (tubal, ovulatory, etc.) include: cigarette smoking; use of alcohol, caffeine, and drugs (prescription and non-prescription); job exposures, including heat, chemicals, and x-radiation; "silent" pelvic inflammatory disease; prior pelvic surgery; douching habits; and in-utero diethylstilbestrol exposure. These exposures will be evaluated using logistic regression techniques which allow estimation of increased risk while controlling for other known risks and potential confounders, such as age and gravidity.